The 2600 put swappable game cartridges into millions of homes. Its first models had a wood-effect front, chunky silver switches and a pair of one-button joysticks.
It was sold for well over a decade. With 128 bytes of memory, programmers squeezed out games for years, finding tricks its designers never imagined.
There was no picture memory at all. The program had to set up every line of the picture as the television beam drew it, a practice known as "racing the beam". Each line had a blocky background, two 8-pixel sprites, two missiles and a ball, from a palette of 128 colours. Changing colours line by line gave its games their bands of colour.
Two channels, each with 16 kinds of buzz, hum and noise and 16 volume steps. Pitch came from dividing a fixed clock, so most notes were out of tune, which gave 2600 music its unmistakable sound.